MSR1 and peritonitis: Here, we report that 1) ITO-NPs induce peritonitis in mice with neutrophil recruitment and IL-1β production that depends on NLRP3 inflammasome and that, 2) endocytosis of ITO-NPs induce caspase1-dependent pyroptosis in macrophages via extracellular interaction with at least SR-A CD204 and caspase1 function, involving intracellular activation of NLRP3-ASC inflammasome and that, 3) MSCs act as a pyroptosis suppressor.